Rear axle - Trumpets with sealed compartment


A sealed compartment, these are also known as "HDE" or Heavy Duty Etanche.
Tractors are fitted with Optimised Heavy Duty trumpets with sealed compartment called "HDEO". Optimised Heavy Duty trumpets trumpets have a crownwheel and sun gears that have been carbon nitrided: this is a special heat treatment that makes them resistant to "pitting." A final honing ensures the optimum bearing of the teeth as a function of the high loads borne by the epicyclic gear. The trumpets bear the right and left hand side axle shafts and contain the final drive units that transmit the rotation from the differential assembly. The trumpets are symmetrical and mounted either side of the centre housing. The final drive unit is lodged in a sealed compartment isolated from the centre housing and containing oil with SAE 85W140 viscosity grade.

Construction
The axle shaft (2) is supported by two opposing taper roller bearings comprising cups (8) (12) and cones (7) (13). The oil tightness of the final drive unit compartment is ensured by lip seal (11) and compartment (30) fitted with seals (31) mounted back-to-back. The oil tightness of the crownwheel (15) is provided by two beads of silicone (Silicomet type). The three lipped seal (5) protects the outer bearing. The planetary carrier (25) engages with the axle shaft (2) via splines, it is made up of three planetary gears (22) that engage with the crownwheel (15) and the sun gear (29). The crownwheel is placed between the trumpet (10) and compartment (30) and is centred via pins (14). The compartment (30) equally serves as the brake plate. The sun gear (29) drives the brake disc (35) through a splined hub (32) held in place by a snap ring (33). The pre-loading of the taper roller bearings is provided by shim(s) (26) placed at the end of the shaft. Axle shaft (2) and planetary carrier (25) are held in place by washer (27) and bolt (28).
The compartment (30) possesses a port "O" providing for lubrication of the brakes (see section 6E01). The tube (38) linked to the breather tube screwed on the left hand-side lifting support allows atmospheric pressure to be maintained in the trumpet.

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Parts list
(2) Straight axle shaft (5) Three-lipped seal (6) Cage (7) Bearing cone (8) Bearing cup (9) Threaded plug (10) Trumpet (11) Seal (12) Bearing cup (13) Bearing cone (14) Pins (15) Crownwheel (16) Tab washer (17) Spacer (18) Bolt(19) Circlip (20) Planetary gear pin (21) Washer (22) Planetary gear
(23) Needle bearings (24) Spacer (25) Planetary carrier (26) Shim(s) (27) Lock washer (28) Bolt (29) Sun gear (30) Brake plate (compartment) (31) Seals (32) Splined hub (33) Snap ring (35) Brake disc (38) Tube (39) Bolt (40) Bolt (41) Filler plug (42) Oil level plug (43) Magnetic drain plug

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Removing and Install the trumpet Assembly


Drain the centre housing.
- The oil used for the mechanical and hydraulic components of the transmission and that used for lubricating the moving parts in the trumpet housings are not the same, their viscosities differ.
- If the oils are not to be changed, they must not be mixed when drained.
Immobilise the tractor. Take off the wheel. Position an axle stand.
Remove the cab fixing bolts and the stabiliser support.
Take out the axle from the lift ram.
Support the trumpet with an appropriate support and a suitable trolley jack.
Remove bolts (39) excluding bolt (40).
Separate the trumpet assembly with the sun gear (29) from the centre housing, the compartment assembly (30) with its markings (31) to (33) and the crownwheel (15) (Fig.3).
- Brake piston "P" remains in the housing (1) (Fig.3)

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Clean the mating faces of the trumpet and centre housings. Remove any traces of previous sealing compound. Dry the parts.
Place a bead of silicone sealing compound (Silicomet type) in angle "D" of the centre housing (1) (Fig.4).
- The diameter of the bead must be uniform, of small section and without joins.

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Replace the brake disc (35) checking that it slides freely on the hub splines.
Support the trumpet using the equipment used when removing it. If necessary, screw two guide studs into the centre housing. Engage the trumpet. Turn the axle shaft and push the trumpet until it makes contact with the housing.
Remove the guide studs if used. Smear the bolts (39) with an oil tightness product ("Plastex" or "Hylomar") and tighten them to a torque of 220 - 300 Nm.
Install the remaining components around the trumpet. Refit the wheel and tighten the wheel nuts or studs to the correct torque depending on the version.
Top up the oil level and check using it in the transparent tube located on the left-hand-side of the centre housing.
- In addition, check the oil level in the final drive unit.
Check the operation of the lift ram. Road test the brake circuit. Check the oil tightness of the trumpet, the hydraulic unions and plugs.

Removing and install the compartment and crownwheel assembly

Remove the trumpet assembly and drain the drive unit concerned.
If possible, place the trumpet in a vertical position, the sun gear at the top. Remove bolt (40), snap ring (33) and hub (32). Unstick and remove compartment (30) having previously place a flexible protection over the splines of the sun gear (29). Remove the sun gear. Release and remove the crownwheel (15) (Fig. 5).



Clean the mating surfaces of the trumpet, the crownwheel and compartment with solvent. Remove all traces of the previous sealing compound. Dry the components.
Seal angles B and C located on the trumpet (10) and the compartment (30) with a Silicone sealing compound (Silicomet type) according to the arrows shown in Fig. 6.
Install the sun gear. Place protector 3376885M1, compartment (30), hub (32), snap ring (33). Replace and tighten bolt (40) to 100 - 130 Nm.
Install the trumpet and top up and check the oil level of the drive unit concerned.

Replacing compartment seals

Remove the trumpet assembly.
Remove the compartment assembly (30) and the crownwheel.
Extract the seals (31).
Using an appropriate assembly, insert the first new seal (31) against the shoulder of compartment (30) with the second seal back to back, employing the same method.
Install the compartment assembly (30) and crownwheel. Install the trumpet assembly.

Removing and Install the planetary Carrier

Remove the trumpet assembly.

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Remove the compartment assembly (30) and crownwheel.
Immobilise the axle shaft and planetary carrier.
Take out bolt (28), washer (27), shim(s) (26). Remove the planetary carrier assembly (25) (Fig. 5).
Take out bolt (18) and spacer (17). Remove snap ring (19) by opening its two extremities.
Drive out and remove the pins (20). Take off the friction washers (21) and the planetary gears. Recover the needle bearings that are arranged in two rows separated by a spacer (24).

Reassembling and refitting the planetary carrier

In the planetary gears, fit the needle bearings (23) previously coated lightly with miscible grease.
Install the planetary gears. Carry out operation 32 in reverse order. Place the spacer (17). Smear bolt (18) with Loctite 270 and tighten to a torque of 34 - 50 Nm.
Check for the presence of washer (16). Install the planetary carrier assembly (25) (Fig.5). If necessary, carry out shimming of the bearings.
Immobilise the axle shaft and planetary carrier. Place the shim(s) (26) and washer (27). Fit and tighten bolt (28), lightly smeared with Loctite 270 or equivalent, to a torque of 340 - 500 Nm.
Install the compartment assembly (30) and crownwheel. Install the trumpet assembly.

Replacing the axle shaft bearings

Remove:
- the trumpet assembly.
- the compartment assembly (30) and crownwheel.
- the planetary carrier assembly (25).
Take off washer (16) and the shaft assembly (2) (bearing cone (13) moves freely on the shaft).
Take off bearing cone (13). Extract bearing cone (7) and seal (5) from the shaft.
Using an extractor or a locally manufactured tool, take off the bearing cups (8) (12) and cage (6).
- When replacing the bearings, it is recommended that the seal (11) is also replaced.
Clean and check the components. Replace any parts found to be defective.

Positioning seal (11)

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Smear the external diameter of the seal with Loctite 542 and insert it 8 mm from the shoulder of bearing cup (12) (Fig.7), the lip turned to face the drive unit.
- If a circumferential groove is present on shaft (2) at the location of seal (11), offset the new seal slightly so that it operates on a different section of the shaft.
Insert:
- cups (8) (12) thrust against their respective shoulders.
- cage (6) according to Fig.8.
- cone (7) previously lubricated and thrust against the shoulder on shaft (2).

Positioning the three-lipped seal (5)

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Insert the new seal thrust against bearing cone (7) and respect the assembly direction (Fig.8).
Moderately grease the cone, seal lips (5) (11) (BP Agricharge grease or equivalent).
Protect the seal lip (11) by temporarily masking the splines on the axle shaft with a flexible protection.
Introduce the prepared shaft into the trumpet fitted with its seal and cups while directing the seal lips towards the exterior. Install cone (13) and refit the tab washer (16).
Install the planetary carrier assembly (25).
Carry out shimming of the bearings.
Install the compartment assembly (30) and crownwheel.
Temporarily replace plug (9) by a grease nipple. Partially fill cavity A (Fig.9) of the trumpet with grease (BP Agricharge or equivalent). Remove the grease nipple. Screw in the plug. Install the trumpet assembly.

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Shimming the axle shaft bearings

Components concerned by shimming
- The axle shaft (2), taper roller bearings (7) (8) (12) (13), the trumpet, tab washer (16) and planetary carrier (25).
- The pre-loading shimming of the taper roller bearings on the axle shaft is carried out via shims (26) placed between the shaft (2) end and washer (27) (Fig.10).

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- To carry out the shimming of the bearings correctly, place the trumpet in a vertical position (Fig.10).
- The bearing cone (13), tab washer (16) and planetary carrier (25) being fitted, place a thickness of shims (26) greater than the space between the end of the axle shaft (2) and the washer (27) thrust face on the planetary carrier (Fig. 11), to obtain a provisional clearance of approximately 0.10 mm to 0.15 mm, in order to be able to carry out definitive shimming and pre-loading.
Place washer (27). Provisionally tighten bolt (28).

Shimming (Fig. 11)

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Press hard on the planetary carrier while simultaneously turning the trumpet several turns.
Place a dial gauge on the planetary carrier with the index positioned towards its centre.
Set the dial gauge to zero.
Using appropriate levers move the planetary carrier vertically.
In relation to the clearance "J" measured, remove a thickness of shims (26) to obtain the pre-loading:
P1 = 0.02 mm to 0.12 mm (Fig. 10) according to J - (0.02 to 0.12)
Definitively fit washer (27) and bolt (28) previously smeared with Loctite 270 or equivalent, tighten to
the torque indicated.